Create a new branch after closing an empty repository fails

[jtpio]

Description

Similar to #1354, but the steps to reproduce the issue may be slightly different.

Reproduce

1. Create a blank repo on GitHub (no README, keep it empty)
2. Clone the repo locally
3. Open JupyterLab
4. From the JupyterLab git UI, create a new branch from main

Expected behavior

It should be possible to create a new branch directly after closing the git repo.

Context

• JupyterLab 4.4.2
• JupyterLab Git: 0.51.1

[jtpio]

cc @gjmooney since you worked on #1363.

Looks like the code path may be slightly different when starting from an already initialized repo, but without any commit yet?